Preventing Overfill Of Media Sheets In a Sheet Feeder

ABSTRACT

A flag with a cam is pivotally attached to a sheet stock edge guide in a sheet loading tray of a copier or printer such that in the event the tray is overfilled, the edge of the sheet stack moves the cam to a position causing the flag to be raised to alert the user of the overfill.

BACKGROUND

The present disclosure relates to sheet feeders for copying and printing machines of the type typically employed in offices and for photocopying documents. Such machines are commonly provided with a user loadable tray for insertion of sheets of the desired size into a feeding mechanism which advances the sheets into the photocopying machine. Trays of this sort intended for loading of at least 50 sheets of paper are provided with adjustable guides on the sides of the tray for maintaining the sheets in accurate registration and position for entry into the feeder. However, if the user overloads the tray the sheets can ride up over the guides and become skewed and enter the feeder in a disoriented manner which can result in improper feeding and jamming. Additionally, it has been found that damage to the sheet sensors in the feeding mechanism can result when jamming occurs. Furthermore, if excessive overload of the tray is experienced, the sheets can become driven into the nudger rolls resulting in damage to the rolls themselves.

Heretofore, attempts to prevent tray overload have been addressed by incorporating a wiper blade for removal of excess paper above a specific height in the tray. If sufficient overload of the tray is encountered, the wiper blade can cause curling of a large number of sheets, which may result in forces applied to the tray components and guides; and, in such situations, failures of these components has been experienced.

It has therefore been desired to provide a way or means of preventing or indicating to the user that the sheet stacker or tray has been overfilled and jamming or damage to the machine may occur. It has further been desired to provide such an indication to the user in a manner which is simple and low in cost to incorporate into existing machines, without adding additional complexity to the loading tray or machine.

SUMMARY

The present disclosure describes a way of indicating to the user that a sheet stacker or tray for a copying machine is overfilled to the point that jamming or damage can occur. The present disclosure describes a rotatable flag pivotally mounted on the sheet edge guides employed in the tray whereby the flag remains in the upright position warning the user of overfill in the event that the sheets are loaded into the stacker or tray above a predetermined level. The flag of the present disclosure may be added to an existing sheet tray edge guide without significant modification of the basic components of the tray and edge guides.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a sheet stacker or tray showing an adjustable edge guide with the overfill indicating flag of the present disclosure mounted thereon.

FIG. 2 is a perspective view of the pivotal flag component of the present disclosure;

FIG. 3 is a perspective view of the flag of FIG. 2 mounted on a retainer;

FIG. 4 is a rear view of the retainer assembly of FIG. 3 mounted on the edge guide of the tray of FIG. 1;

FIG. 5 is an edge view of the flag of the present disclosure in the upright or indicating position in solid outline and the retracted position shown in dashed line;

FIG. 6 is a perspective view of an existing sheet stacker or tray with the elevate plate in place; and,

FIG. 7 is a view similar to FIG. 6, with the elevate plate removed.

DETAILED DESCRIPTION

Referring to FIGS. 6 and 7, an example of a prior art sheet stacker or tray assembly is indicated generally at 100, and includes front and rear triple towered sheet edge guides 102, 104 respectively and an adjustable side or length edge guide 106 adjustably mounted on the deck 108 of the assembly 100. The sheet stack (not shown) when loaded into tray 10 registers against the side rail 110 of the tray.

Edge guides 102, 104, each have a leg portion or extension 112, 114 respectively with a toothed rack 116, 118 respectively along one side of the leg portion 112, 114. The teeth of the racks 116, 118 engage respectively opposite sides of stationary toothed pinions 120, 122 to provide equal and oppositely directed movement of the edge guide upon user adjustment, for effecting centering of the sheet stack in the tray.

It will be noted that the center tower of edge guide 104 has the inscription “MAX” thereon above a visible fill limit line for indicating to the user the level above which the tray should not be filled.

Referring to FIG. 1, a portion of a stacker or a sheet loading tray for a copy or printing machine in accordance with the present disclosure is indicated generally at 10 and has a rear edge guide with towers 12, 14, 16 attached to a bar or strap 18 which has a leg or portion 20 thereof extending generally at right angles thereto which may be formed integrally therewith and which is slidably received on the base or bottom 24 of the tray. Guide surfaces 17, 21 are provided on the end of strap 18-T for engaging corresponding guide surfaces (not shown) on base 24. The leg portion 20 may include a notched rack 26 for engagement by a toothed pin (not shown) similar to pinions 120, 122 of FIG. 7 for securing the guides 12, 14, 16 in a desired position for the selected print media sheets in a manner well known in the design of sheet trays.

The center edge guide tower 14 has provided thereon an overfill indicator indicated generally at 28 provided thereon for providing visual indication to the user that the tray has been filled above the safe limit level as will hereinafter be described.

Referring to FIG. 2, the indicator 28 comprises the tab or flag 30 which has a pair of oppositely extending half axles or trunnions 32, 34 formed thereon with a cam 36 extending from trunnion 32 and oriented to be aligned with the flag 30 and extend from the opposite side of the trunnion 32.

Referring to FIG. 3, the indicator 28 is shown with the trunnions 32, 34 received in a retainer 38 and snap locked therein for pivotal movement with respect thereto. The retainer 38 has a slot or notch 40 to provide clearance for cam 36 to rotate with the flag 30. Retainer 38 may be provided with a pair of mounting towers 42, 44 each centrally apertured as denoted respectively by reference numerals 50, 52 for receiving suitable fasteners therethrough.

Referring to FIG. 4, the retainer 38 is shown as positioned on the back side of edge guide 14 with the towers 42, 44 positioned for receiving mounting screws (not shown) therethrough for attachment to the edge guide 14. The flag 30 is shown in FIG. 4 in the retracted or horizontal position.

Referring to FIG. 5, the tray assembly 10 is shown in edge view with the indicator 28 shown in solid outline with the flag 30 disposed vertically upward to provide an indication to the user that the tray has been filled to the limit. In the position shown in solid outline, the indicator 28 has cam 36 held in a downward position by the edge 56 of the sheet stack which has its top surface denoted by reference numeral 54. If the top surface of the sheet stack 54 is below the position of cam 36 shown in solid outline in FIG. 5, the cam 36 will not be held in the downward position; and, the indicator, under the force of gravity, will rotate counterclockwise to the position shown in dashed outline thereby retracting the flag 30 and raising the cam 36 to the horizontal position shown in dashed outline.

Thus, the present disclosure describes a unique and novel indicator assembly which may be attached to the edge guide of a media sheet tray or stacker for providing a visual indicator or flag which is raised upon the user loading the tray above the fill limit.

It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. 

1. A device for preventing overfill of media sheets in a sheet feeder comprising: (a) a user loadable tray for positioning media sheets therein and adapted for use with the feeder; and, (b) an indicator disposed with the tray, wherein upon user fill of sheets in the tray above a predetermined level, the indicator is moved by the sheets from a retracted position to an active position providing an indication of overfill.
 2. The device defined in claim 1, wherein the indicator in the active position includes a stop operative to block insertion of the tray into the feeder.
 3. The device defined in claim 1, wherein the tray includes sheet position edge guides and the indicator is pivotally mounted on one of the guides.
 4. The device defined in claim 1, wherein the indicator is pivotally mounted on a rear sheet edge guide of the tray.
 5. The device defined in claim 1, wherein the indicator is operative to display a flag readily visible to the user.
 6. The device defined in claim 1, wherein the tray includes guides with integrally formal surfaces for pivoting the indicator thereon.
 7. The device defined in claim 1, wherein the guides includes surfaces operative to limit movement of the indicator in the active position.
 8. The device defined in claim 1, wherein the indicator is pivotally mounted onto a retainer and forms a subassembly which is attached to the tray.
 9. The device defined in claim 8, wherein the retainer includes integrally formed surfaces operable to pivotally engage and retain the indicator thereon.
 10. The device defined in claim 8, wherein the subassembly is attached to a sheet guide on the tray.
 11. The device defined in claim 1, wherein the indicator is mounted on a sheet guide on the tray and the sheet guide includes surfaces operable to limit movement of the indicator.
 12. A method of preventing overfill of media sheets in a sheet feeder comprising: (a) providing a user loadable tray for positioning media sheets therein for insertion into the feeder; (b) disposing an indicator with the tray and moving the indicator from a retracted to an active indicating position in response to an overfill.
 13. The method defined in claim 12, wherein the step of disposing an indicator includes disposing an indicator on the tray for pivotal movement thereon.
 14. The method defined in claim 12, wherein the step of providing a tray includes providing adjustable sheet edge guides and the step of disposing an indicator includes pivotally mounting an indicator on one of the guides.
 15. The method defined in claim 14, wherein the step of disposing an indicator includes pivotally attaching an indicator to a retainer and mounting the retainer on one of the sheet edge guides. 